Nobody is sure why the cities, farms, and remote monasteries of the Earthlike planet Areth were abandoned. But the Areth Research Commission is devoted to documenting what it can about Areth civilization, based on the architecture it left behind.

With his online science fiction art book Areth: An Architectural Atlas, artist Adam Ryder has created an incredible document of xenopology, filled with gorgeous architectural photographs and strangely melancholy scientific notes about the beings who built the world he's captured.

Ryder wrote to io9 to explain a little about the project:

The buildings in the photographs are real places, mostly in the Southwest that have been made to appear as if they reside on a cloudy, yellowy planet. Each site in the Atlas is accompanied by text which speculates anthropologically about the function of each building and about the lost civilization which created it.

Given that these buildings are actually on Earth, it's no surprise that Arethean cultures are in some ways a distorted reflection of Earth cultures. Unlike our warlike civilizations, though, Aretheans never engaged in industrial warfare. Instead, they lived collectively and settled their disputes in court. They appear to have devoted much time to developing technologies to control their planet's strange weather, as well as power plants that harvested electrical energy from the atmosphere. Though technologically not much more advanced than Earth civilization, Areth's peoples had an extensive renewable energy network, scientific observation posts, and highly efficient farms. I love the section wehre Ryder describes the weird Arethean apiary, where they raised mouse-sized "bees" that created a honey-like substance used to make an intoxicant like wine or beer.

The Aretheans had a matriarchal religion, and their idea of entertainment is a complete inversion of ours on Earth. When Aretheans went to the theater, the vast majority of people would perform for a very tiny audience sitting in a small area beneath the enormous, wrap-around stage.

Reading the descriptions of this lost civilization, it's hard not to feel like it's a the story of what Earth civilizations might have become if we had taken a slightly different direction. What if we'd never had industrial warfare, or had focused on renewable energy before we delved into our fossil fuel stores? That the Aretheans have mysteriously disappeared makes this idea almost irresistible, as if we're visiting a vanished timeline so close to being our own that it has left an entire built environment behind.

You can read Ryder's whole book, and see more amazing photographs, on his website.